Ketone bodies produced by sodium-glucose cotransporter 2 (SGLT2) inhibitors can be advantageous, providing an efficient and stable energy source for the brain and muscles. However, in patients with diabetes, ketogenesis induced by SGLT2 inhibitors may be harmful, potentially resulting in severe diabetic ketoacidosis (DKA). During fasting, ketone body production serves as an alternative and efficient energy source for the brain by utilizing stored fat, promoting mental clarity, and reducing dependence on glucose. The concurrent use of SGLT2 inhibitors during perioperative fasting may further elevate the risk of euglycemic DKA. We describe a case of DKA that occurred during perioperative fasting in a patient receiving empagliflozin, an SGLT2 inhibitor. This case underscores the importance of recognizing the potential risk of DKA in patients with diabetes using SGLT2 inhibitors during perioperative fasting.

Purpose: The current study provides national cancer statistics and their secular trends in Korea, including incidence, mortality, survival, and prevalence in 2022, with international comparisons. Materials and Methods: Cancer incidence, survival, and prevalence rates were calculated using the Korea National Cancer Incidence Database (1999-2022), with survival follow-up until December 31, 2023. Mortality data obtained from Statistics Korea, while international comparisons were based on GLOBOCAN data. Results: In 2022, 282,047 newly diagnosed cancer cases (age-standardized rate [ASR], 287.0 per 100,000) and 83,378 deaths from cancer (ASR, 65.7 per 100,000) were reported. The proportion of localized-stage cancers increased from 45.6% in 2005 to 50.9% in 2022. Stomach, colorectal, and breast cancer showed increased localized-stage diagnoses by 18.1, 18.5, and 9.9 percentage points, respectively. Compared to 2001-2005, the 5-year relative survival (2018-2022) increased by 20.4 percentage points for stomach cancer, 7.6 for colorectal cancer, and 5.6 for breast cancer. Korea had the lowest cancer mortality among countries with similar incidence rates and the lowest mortality-to-incidence (M/I) ratios for these cancers. The 5-year relative survival (2018-2022) was 72.9%, contributing to over 2.59 million prevalent cases in 2022. Conclusion Since the launch of the National Cancer Screening Program in 2002, early detection has improved, increasing the diagnosis of localized-stage cancers and survival rates. Korea recorded the lowest M/I ratio among major comparison countries, demonstrating the effectiveness of its National Cancer Control Program.

Purpose: The metabolism of tamoxifen is influenced by various cytochrome p450 enzymes, including CYP2D6 and CYP2C19, leading to variations in the levels of endoxifen, even with the same tamoxifen dose. However, the clinical significance of endoxifen for the prognosis of breast cancer patients remains controversial. This study aimed to elucidate the relevance of endoxifen level to recurrence-free survival censored with tamoxifen discontinuation (RFSt), representing the RFS for tamoxifen itself, of breast cancer patients and determine a suitable cutoff for prognostication. Materials and Methods: The study included 478 breast cancer patients. Tamoxifen and its metabolites, including endoxifen, were measured using liquid chromatography-tandem mass spectrometry. An optimal cutoff was determined with maximally selected rank statistics. Survival analysis and Cox regression were conducted based on this cutoff. Results: An endoxifen level of 21.00 ng/mL was the optimal cutoff for prognostication. Survival analysis revealed a statistically significant difference in RFSt between the low endoxifen group (≤ 21.00 ng/mL) and the high endoxifen group (> 21.00 ng/mL) (log-rank test, p=0.032). The 10-year probability of RFSt was 83.2% (95% confidence interval [CI], 77.0 to 89.9) and 88.3% (95% CI, 83.3 to 93.5) in the low and high endoxifen groups, respectively. Multivariable Cox proportional hazards regression indicated endoxifen concentration as a significant factor associated with prognosis. Conclusion Endoxifen could serve as a marker for appropriate tamoxifen treatment with a cutoff of 21.00 ng/mL. Based on this cutoff, therapeutic drug monitoring would benefit patients displaying suboptimal endoxifen concentrations.

Background: The advantages of using an acellular dermal matrix (ADM) for implantbased breast reconstruction in breast cancer patients are well-documented across multiple studies. However, there have been no previous instances of using multilayered ADM for reconstruction following breast-conserving surgery (BCS). This study evaluated the outcomes of breast reconstruction employing multilayered ADM for volume replacement using a local glandular flap post-BCS, and aims to underscore the advantages of this surgical approach. Methods: Breast cancer patients who underwent BCS using several layers of ADM from August 2016 to December 2019 were retrospectively reviewed. Only patients with at least 3 years of follow-up were included in this study. The anticipated postoperative complications were breast deformity, seroma, hematoma, and infection. Results: Seventy-four patients were included in this study. Most patients experienced symptoms of hard palpation at the reconstruction site, which indicated the surface of the ADM inserted into the breast. Ten patients developed breast deformities, accounting for 13.5% of the cases, and required surgical correction. Other complications were less frequent: four patients (5.3%) had a confirmed seroma for 6 months or longer, two patients (2.6%) experienced fat necrosis, and one patient (1.3%) underwent re-operation to remove the ADM. Conclusions Reconstruction with a glandular flap and ADM following BCS is generally simpler and requires less surgical time compared to using a latissimus dorsi flap or other local flaps. Additionally, it avoids complications at the donor site, presenting a feasible surgical alternative for BCS in breasts with small defects.

Ketone bodies produced by sodium-glucose cotransporter 2 (SGLT2) inhibitors can be advantageous, providing an efficient and stable energy source for the brain and muscles. However, in patients with diabetes, ketogenesis induced by SGLT2 inhibitors may be harmful, potentially resulting in severe diabetic ketoacidosis (DKA). During fasting, ketone body production serves as an alternative and efficient energy source for the brain by utilizing stored fat, promoting mental clarity, and reducing dependence on glucose. The concurrent use of SGLT2 inhibitors during perioperative fasting may further elevate the risk of euglycemic DKA. We describe a case of DKA that occurred during perioperative fasting in a patient receiving empagliflozin, an SGLT2 inhibitor. This case underscores the importance of recognizing the potential risk of DKA in patients with diabetes using SGLT2 inhibitors during perioperative fasting.

Purpose: Breast cancer gene (BRCA) mutation is a well-known risk factor for breast cancer, and clinical interest in prophylactic mastectomy has increased in recent years.We investigated patients who were BRCA mutation carriers and underwent contralateral risk-reducing mastectomy (RRM), focusing on the incidence of occult malignancy after contralateral RRM. Methods: Prospectively collected data of patients with breast cancer treated at a single institution were retrospectively reviewed. Patients who underwent RRM with BRCA mutation who underwent RRM between January 2010 and November 2023 were included in this study.Among patients who underwent contralateral RRM, those with a primary cancer diagnosis were included, and those with occult malignancy on the contralateral RRM side were reviewed additionally. The demographics and pathologies of both primary breast cancer and occult malignancies were evaluated. Results: In our institution, 925 patients were identified as BRCA mutation carriers, and 320 patients underwent contralateral RRM along with primary breast cancer surgery. BRCA2 mutation occurred more frequently (54.8%) in the overall BRCA mutation cohort. Furthermore, we reviewed 320 patients diagnosed with breast cancer and detected as BRCA mutation carriers who underwent contralateral RRM; high proportion of them were BRCA1 mutation carriers.Interestingly, we found a low incidence of only seven patients (2.2%) with occult malignancy on contralateral RRM side, which is different from that reported in other nations. Conclusion The incidence of occult malignancy in the contralateral breast of breast cancer patients with breast cancer with BRCA mutation is significantly low, and may be influenced by several factors. Increased utilization of screening and advancements in diagnostic technologies in South Korea have reduced the chance of occult malignancy in RRM, and a variety of pathologic examination methods may affect the rate of incidence.

Background: The advantages of using an acellular dermal matrix (ADM) for implantbased breast reconstruction in breast cancer patients are well-documented across multiple studies. However, there have been no previous instances of using multilayered ADM for reconstruction following breast-conserving surgery (BCS). This study evaluated the outcomes of breast reconstruction employing multilayered ADM for volume replacement using a local glandular flap post-BCS, and aims to underscore the advantages of this surgical approach. Methods: Breast cancer patients who underwent BCS using several layers of ADM from August 2016 to December 2019 were retrospectively reviewed. Only patients with at least 3 years of follow-up were included in this study. The anticipated postoperative complications were breast deformity, seroma, hematoma, and infection. Results: Seventy-four patients were included in this study. Most patients experienced symptoms of hard palpation at the reconstruction site, which indicated the surface of the ADM inserted into the breast. Ten patients developed breast deformities, accounting for 13.5% of the cases, and required surgical correction. Other complications were less frequent: four patients (5.3%) had a confirmed seroma for 6 months or longer, two patients (2.6%) experienced fat necrosis, and one patient (1.3%) underwent re-operation to remove the ADM. Conclusions Reconstruction with a glandular flap and ADM following BCS is generally simpler and requires less surgical time compared to using a latissimus dorsi flap or other local flaps. Additionally, it avoids complications at the donor site, presenting a feasible surgical alternative for BCS in breasts with small defects.

Purpose: The current study provides national cancer statistics and their secular trends in Korea, including incidence, mortality, survival, and prevalence in 2022, with international comparisons. Materials and Methods: Cancer incidence, survival, and prevalence rates were calculated using the Korea National Cancer Incidence Database (1999-2022), with survival follow-up until December 31, 2023. Mortality data obtained from Statistics Korea, while international comparisons were based on GLOBOCAN data. Results: In 2022, 282,047 newly diagnosed cancer cases (age-standardized rate [ASR], 287.0 per 100,000) and 83,378 deaths from cancer (ASR, 65.7 per 100,000) were reported. The proportion of localized-stage cancers increased from 45.6% in 2005 to 50.9% in 2022. Stomach, colorectal, and breast cancer showed increased localized-stage diagnoses by 18.1, 18.5, and 9.9 percentage points, respectively. Compared to 2001-2005, the 5-year relative survival (2018-2022) increased by 20.4 percentage points for stomach cancer, 7.6 for colorectal cancer, and 5.6 for breast cancer. Korea had the lowest cancer mortality among countries with similar incidence rates and the lowest mortality-to-incidence (M/I) ratios for these cancers. The 5-year relative survival (2018-2022) was 72.9%, contributing to over 2.59 million prevalent cases in 2022. Conclusion Since the launch of the National Cancer Screening Program in 2002, early detection has improved, increasing the diagnosis of localized-stage cancers and survival rates. Korea recorded the lowest M/I ratio among major comparison countries, demonstrating the effectiveness of its National Cancer Control Program.

Purpose: The metabolism of tamoxifen is influenced by various cytochrome p450 enzymes, including CYP2D6 and CYP2C19, leading to variations in the levels of endoxifen, even with the same tamoxifen dose. However, the clinical significance of endoxifen for the prognosis of breast cancer patients remains controversial. This study aimed to elucidate the relevance of endoxifen level to recurrence-free survival censored with tamoxifen discontinuation (RFSt), representing the RFS for tamoxifen itself, of breast cancer patients and determine a suitable cutoff for prognostication. Materials and Methods: The study included 478 breast cancer patients. Tamoxifen and its metabolites, including endoxifen, were measured using liquid chromatography-tandem mass spectrometry. An optimal cutoff was determined with maximally selected rank statistics. Survival analysis and Cox regression were conducted based on this cutoff. Results: An endoxifen level of 21.00 ng/mL was the optimal cutoff for prognostication. Survival analysis revealed a statistically significant difference in RFSt between the low endoxifen group (≤ 21.00 ng/mL) and the high endoxifen group (> 21.00 ng/mL) (log-rank test, p=0.032). The 10-year probability of RFSt was 83.2% (95% confidence interval [CI], 77.0 to 89.9) and 88.3% (95% CI, 83.3 to 93.5) in the low and high endoxifen groups, respectively. Multivariable Cox proportional hazards regression indicated endoxifen concentration as a significant factor associated with prognosis. Conclusion Endoxifen could serve as a marker for appropriate tamoxifen treatment with a cutoff of 21.00 ng/mL. Based on this cutoff, therapeutic drug monitoring would benefit patients displaying suboptimal endoxifen concentrations.

Purpose: Breast cancer gene (BRCA) mutation is a well-known risk factor for breast cancer, and clinical interest in prophylactic mastectomy has increased in recent years.We investigated patients who were BRCA mutation carriers and underwent contralateral risk-reducing mastectomy (RRM), focusing on the incidence of occult malignancy after contralateral RRM. Methods: Prospectively collected data of patients with breast cancer treated at a single institution were retrospectively reviewed. Patients who underwent RRM with BRCA mutation who underwent RRM between January 2010 and November 2023 were included in this study.Among patients who underwent contralateral RRM, those with a primary cancer diagnosis were included, and those with occult malignancy on the contralateral RRM side were reviewed additionally. The demographics and pathologies of both primary breast cancer and occult malignancies were evaluated. Results: In our institution, 925 patients were identified as BRCA mutation carriers, and 320 patients underwent contralateral RRM along with primary breast cancer surgery. BRCA2 mutation occurred more frequently (54.8%) in the overall BRCA mutation cohort. Furthermore, we reviewed 320 patients diagnosed with breast cancer and detected as BRCA mutation carriers who underwent contralateral RRM; high proportion of them were BRCA1 mutation carriers.Interestingly, we found a low incidence of only seven patients (2.2%) with occult malignancy on contralateral RRM side, which is different from that reported in other nations. Conclusion The incidence of occult malignancy in the contralateral breast of breast cancer patients with breast cancer with BRCA mutation is significantly low, and may be influenced by several factors. Increased utilization of screening and advancements in diagnostic technologies in South Korea have reduced the chance of occult malignancy in RRM, and a variety of pathologic examination methods may affect the rate of incidence.